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Air conditioner freeze overs are probably more common than you might think. However, the issues that cause freeze overs vary widely. If your air conditioner keeps freezing over, you can look at a couple of different things to identify the problem. These range from DIY fixes to needing to call the professionals in. We have created a quick guide to help you understand the possible issues so that you can keep your air conditioner vibing cold sensations all summer long.

Need air conditioning assistance in Brisbane? call the team on 0403 254 272

Restricted airflow

Probably the most common is when you have restricted airflow, good airflow through the evaporator coils is essential to prevent your system from freezing over. When your system has insufficient airflow, there is not enough heat transferred from the air to the evaporator coils, which will cause the coils to develop an ice layer.

So what can cause your system to have insufficient or restricted airflow?

Clogged Air Filter - Ice on coils

Clogged air filter

The easiest fix, and the one you’re likely praying for, is a clogged air filter. Over time, dust and mould can build up on the air filter, preventing air from flowing through the system efficiently. The fix to this solution can be as simple as taking out the air filter for cleaning or purchasing a replacement filter for installation, depending on your system.

Blower fan malfunctioning

A faulty blower fan in your head unit can also cause you issues; this can vary from limited airflow from the fan to the blower fan not functioning at all. A technician will be required to inspect the system to diagnose, fix or replace any broken parts.

Other Issues:

If you have assessed your air filter and blower fan and found them to both be ok, you may have one of the following issues.

Refrigerant leaks and pressure

Another common issue that will require a technicians attention is when your system has low refrigerant or a change in the pressure of the refrigerant components. When you have a refrigerant leak, the system will continue to operate however the pressure drop can cause the temperature of the evaporator coils to dip below freezing point. Moisture from the air flowing through will freeze on the coils during operation and slowly build an ice layer. This ice layer will then prevent any air from passing through the coils. Another issue that could cause an issue with your refrigerants pressure is a kink in the refrigerant line. The change in pressure will again cause your evaporator coils to start freezing over.

Clogged condensate drain line

Your air conditioner cools the air by absorbing the latent heat and transferring the heat outside. Like on a cold glass of water, the moisture from the air will condensate as the air temperature drops. Your air conditioner collects the condensation with a drip pan, and a drain line moves the collected water outside. However, when this drain line clogs, the collected water will back up and eventually overflow, leaking from your system and making your air conditioner more susceptible to freezing over. This issue will require a technicians visit to unclog the drain line.


You may even have a faulty thermostat. In an air conditioning system, the thermostat monitors the air temperature and turns the compressor on or off. If the temperature control is defective, the compressor can run continuously and bring the air temperature to a point where it can no longer remove heat, and the coils will begin to freeze over. This issue will require a technicians visit and possible part replacement.

Advanced Climate Solutions

Advanced Climate Solutions offers comprehensive air conditioning services Brisbane wide, from AC supply and installation, to ongoing support, servicing, and repairs. ACS is a leader in delivering safe and reliable aircon services in Queensland. Our highly trained staff are very knowledgeable in ducting and air conditioner systems, with experience in both commercial and residential air conditioning services. No matter what your air conditioning needs may be, we’ll find the best AC solution for you. Call Advanced Climate Solutions today on 0403 254 272.